Patents Represented by Attorney, Agent or Law Firm Jamie Wiegand
  • Patent number: 6617992
    Abstract: A method and apparatus are arranged for minimizing the effects of capacitor mismatch errors in pipelined analog-to-digital converters (ADC). The virtual elimination of capacitor mismatch effects is achieved without trading comparator-offset margin by an appropriate selection of comparator circuits' reference signals and the inclusion of a plurality of capacitors that are switched into an appropriate feedback position. The appropriate feedback position in the switched capacitor amplifier circuit is determined based on the operating region. For each of k pipeline stage, a method includes: determining an operating region of a sampled analog input signal for a predetermined transfer curve, and computing digital code bits and an improved residue signal for this stage based on the determined operating region, and then computing a final conversion code from the digital code bits of the k pipeline stages.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: September 9, 2003
    Assignee: National Semiconductor Corporation
    Inventor: Satoshi Sakurai
  • Patent number: 6600440
    Abstract: A method and apparatus are arranged for minimizing the effects of capacitor mismatch errors in pipelined analog-to-digital converters (ADC). The virtual elimination of capacitor mismatch effects is achieved without trading comparator offset margin by an appropriate selection of comparator circuits' reference signals and the inclusion of a plurality of capacitors that are switched into an appropriate feedback position. The appropriate feedback position in the switched capacitor amplifier circuit is determined based on the operating region. For each of k pipeline stage, a method includes: determining an operating region of a sampled analog input signal for a predetermined transfer curve, and computing digital code bits and an improved residue signal for this stage based on the determined operating region, and then computing a final conversion code from the digital code bits of the k pipeline stages.
    Type: Grant
    Filed: August 15, 2001
    Date of Patent: July 29, 2003
    Assignee: National Semiconductor Corporation
    Inventor: Satoshi Sakurai